The invention relates to electrochromic arrangements in a layered structure which are characterized in that one layer contains an electrically conductive electrochromic polydioxythiophene, another layer comprises an electrolyte containing a protonic acid, and another layer comprises an ion storage or a mixture of ion storages.

This application is the National Stage Application of PCT/EP99/07104, which claims a priority from German Application 198 45 881.9, filed Oct. 6, 1998.
The present invention relates to electrochromic assemblies having controllable light transmittance, their production and their use.
Windows of vehicles have hitherto not been able to be regulated in terms of their transparency to electromagnetic radiation. Phototropic glasses have hitherto only been used for spectacles and have only a relatively small change in the transmission. Windows in buildings have hitherto been darkened using curtains, shutters, roller blinds or other movable mechanical elements. Electrochromic devices can thus be applied in many ways. In summary, examples are:
1. Vehicle Glazing (window panes or sunroofs in cars)
An electrochromic device is suitable for protection against sun or dazzling in motor vehicles. Front, side and rear windows or glass roofs can be included. The degree of darkening can be matched zonewise and steplessly to the needs of the driver, to the state of the sun and to the current driving situation. Integration into a computerized control system is possible. A combination of the active element with a composite glazing unit is likewise possible, for example application of a film system to panes of safety glass.
The transmittance of the panes can be controlled manually or automatically, which can be used for effective protection against dazzling during night driving, automatic adjustment of the brightness level when driving in and out of tunnels and multistorey carparks and for protection against breaking-in and theft of the parked vehicle by preventing vision into the vehicle interior. Excessive heating of the interior in summer, particularly in the case of a parked vehicle, can be prevented (cf. EP-A 0 272 428).
2. Glazing of Buildings (electrochromic window)
In buildings, electrochromic assemblies are suitable for darkening side windows and skylights of buildings, dwelling rooms, workrooms or greenhouses as controllable protection against sun (visible spectral region) and heat (IR region) and for protecting the eyes (visible spectral region). For protection against break-ins, glazing of bank counters or display windows can be darkened at the press of a button. Glass doors can be made visible automatically on approach of a person in order to avoid injury. The opportunity of producing virtually all shades of colour also makes it possible to blend the glazing into the facade of a building. The energy consumption for controlling the transparency of large areas of window is low, particularly when the memory effect of the system can be exploited and energy is only consumed in the switching phase. A combination with heat-protection glazing (K glass) is very suitable for achieving dynamic control of solar radiation through a window (xe2x80x9csmart windowxe2x80x9d). An electrochromic system can thus contribute to regulating and limiting the energy necessary for air conditioning of a building.
The voltage supply to the system can also be provided by solar modules. A light-sensitive sensor can determine the degree of solar radiation and thus control the light transmittance.
3. Display Elements
The ability to produce attractive colours and the large-area portrayal of any contours, e.g. letters, figures, signs and symbols (able to be produced by means of suitable structuring techniques) provides advertising with an interesting medium. Decorative and informative effects are readily possible.
Apart from the possibility of arranging the system between panes of glass, there is also the alternative of using two or even only one transparent plastic film as support. This makes possible poster-like advertising media with changeable information.
Electrochromic devices can be used for small display elements such as faces of clocks or dials of measuring instruments, displays for a wide variety of applications and for large display elements such as traffic signs, advertising columns, information displays at railway stations, airports or for parking direction systems. Use as a variable delineation system (playing area boundaries, etc.) in sports halls is likewise possible.
The use of such systems is generally possible wherever information is to be made visible.
4. Optics
In optics, electrochromic systems can be used either in combination with glasses, lenses and filters of other optical instruments or as sole actively used component. Their use as lap dissolve protection for optical detection systems is likewise possible. The system is likewise suitable as a controllable filter system in photographic processes.
5. Mirrors
An electrochromic device can also be used as a dimmable mirror, e.g. in an automobile as external or rear-view mirror which can be darkened by application of an electric potential and thus prevents dazzling by the headlights of other vehicles (cf., for example, U.S. Pat. No. 3,280,702, U.S. Pat. No. 4,902,108 (Gentex), EP-A 0435 689, U.S. Pat. No. 5,140,455). A disadvantage of systems according to the prior art (solution systems) is the colour inhomogeneity after prolonged operation (segregation), particularly in the case of large mirrors (e.g. mirrors for heavy goods vehicles). Increasing the viscosity of the solution system by addition of polymeric thickeners has been described (e.g. U.S. Pat. No. 4,902,108).
6. EMI Shielding
An electrochromic device can also be used as a variable filter element for the modulation of electromagnetic radiation in certain wavelength regions.
Electrochromic devices normally comprise a pair of glass or plastic plates of which, in the case of a mirror, one is mirrored. One side of these plates is coated with a light-transparent, electrically conductive layer, e.g. indium-tin oxide (ITO). A cell is built up from these plates by fixing them with their electroconductively coated sides facing one another; the cell between the plates contains the electrochromic system. It is tightly sealed. The two plates can be separately provided with electric contacts and controlled via the conductive layers.
The electrochromic solution systems known from the above-cited prior art contain, in a solvent, pairs of redox substances which form coloured, positively or negatively charged, chemically reactive free radicals after reduction or oxidation. Examples are the viologen systems which have been known for a long time.
The pair of redox substances used here is in each case a reducible and an oxidizable substance. Both are colourless or have only a slight colour. Under the action of an electric potential, one substance is reduced and the other is oxidized, at least one becoming coloured. After switching off the potential, the two original redox substances are reformed, with decoloration or lightening of colour occurring.
It is known from U.S. Pat. No. 4,902,108 that suitable pairs of redox substances are those whose reducible substance has at least two chemically reversible reduction waves in the cyclic voltammogram and the oxidizable substance correspondingly has at least two chemically reversible oxidation waves. Systems of this type are suitable mainly for dimmable rear-view mirrors in cars. Since these are solution systems, use in electrochromic windows is not a possibility under normal circumstances.
Also known are systems in which the actual electrochromic redox pair is dispersed in a polymer matrix (see, for example, WO-A 96/03475). The undesirable effect of segregation is suppressed here.
Combinations of inorganic electrochromic components such as WO3, NiO or IrO2 are likewise known and are possibilities as components in an electrochromic window (see, for example, U.S. Pat. No. 5,657,149, Electronique International No. 276,16 (1997)).
These inorganic electrochromic components can be applied to the conductive substrate only by vapour deposition, sputtering or the sol-gel technique. As a result, systems of this type are very expensive to produce. In the context of efforts to replace an inorganic component by an organic polymer component, electrochromic systems, for example, based on the electrically conductive polymer polyaniline (PANI) and WO3 as complementary electrochromic materials have become known (see, for example, B. P. Jelle, G. Hagen, J. Electrochem. Soc., Vol. 140, No. 12,3560 (1993)). An attempt has also been made to use systems without an inorganic component, where the ITO or SnO2 layer (counterelectrode) is supposed to serve as complementary electrochromic component to substituted poly(3,4-ethylenedioxy-thiophenes) (U.S. Pat. No. 5,187,608).
However, it is found that such electrochromic assemblies are unsuitable for ensuring a sufficient number of switching cycles without a change in the device properties. In addition, the electrochromic switching process by means of lithium ions is not fast enough for some applications. It has now been found that protons in the electrolyte layer in combination with poly-(3,4-dioxythiophenes) lead to a significantly shorter switching time.
The present invention provides electrochromic assemblies having a layer structure, characterized in that one layer comprises an electrically conductive, electrochromic polydioxythiophene, a further layer comprises an electrolyte containing a protic acid (Brpnsted acid) and a further layer comprises an ion reservoir compound or a mixture of ion reservoir compounds.
The polydioxythiophenes are cationically charged and built up of structural units of the formula (I)
where
A1 and A2 represent, independently of one another, substituted or unsubstituted (C1-C4)-alkyl or together form substituted or unsubstituted (C1-C4)-alkylene, and
n represents an integer from 2 to 10,000, preferably from 5 to 5000,
in the presence of polyanions.
Preferred cationic polydioxythiophenes are built up of structural units of the formula (Ia) or (Ib)
where
R1 and R2 represent, independently of one another, hydrogen, substituted or unsubstituted (C1-C18)-alkyl, preferably (C1-C10)-, in particular (C1-C6)-alkyl, (C2-C12)-alkenyl, preferably (C2-C8)-alkenyl, (C3-C7)-cycloalkyl, preferably cyclopentyl, cyclohexyl, (C7-C15)-aralkyl, preferably phenyl-(C1-C4)-alkyl, (C6-C10)-aryl, preferably phenyl, naphthyl, (C1-C18)-alkyloxy, preferably (C1-C10)-alkyloxy, for example methoxy, ethoxy, n- or iso-propoxy, or (C2-C18)-alkyloxy ester and
R3 and R4 represent, independently of one another, hydrogen, but not both at the same time, or (C1-C18)-alkyl, preferably (C1-C10)-, in particular (C1-C6)-alkyl, (C2-C12)-alkenyl, preferably (C2-C8)-alkenyl, (C3-C7)-cycloalkyl, preferably cyclopentyl, cyclohexyl, (C7-C,5)-aralkyl, preferably phenyl-(C1-C4)-alkyl, (C6-C10)-aryl, preferably phenyl, naphthyl, (C1-C18)-alkyloxy, preferably (C1-C10)-alkyloxy, for example methoxy, ethoxy, n- or iso-propoxy or (C2-C18)-alkyloxy ester, each substituted by at least one sulphonate group,
n represents from 2 to 10,000, preferably from 5 to 5000.
Very particularly preferably, the electrochromic assembly of the invention contains at least one electrically conductive, electrochromic cationic or uncharged polydioxythiophene of the formula (IIa) and/or (IIb)
where
R3 is as defined above,
n represents an integer from 2 to 10,000, preferably from 5 to 5000.
As polyanions, use is made of the anions of polymeric carboxylic acids such as polyacrylic acids, polymethacrylic acids or polymaleic acids and polymeric sulphonic acids such as polystyrenesulphonic acids and polyvinylsulphonic acids. These polycarboxylic and polysulphonic acids can also be copolymers of vinylcarboxylic and vinylsulphonic acids with other polymerizable monomers such as acrylic esters and styrenes.
Particular preference is given to the anion of polystyrenesulphonic acid as counterion.
The molecular weight of the polyacids which give the polyanions is preferably from 1000 to 2,000,000, particularly preferably from 2000 to 500,000. The polyacids or their alkali metal salts are commercially available, e.g. polystyrenesulphonic acids and polyacrylic acids, or can be prepared by known methods (see, for example, Houben Weyl, Methoden der organischen Chemie, Volume E 20 Makromolekulare Stoffe, Part 2, (1987), p. 1141 ff).
In place of the free polyacids required for forming the dispersions of polydioxythiophenes and polyanions, it is also possible to use mixtures of alkali metal salts of the polyacids and corresponding amounts of monoacids.
In the case of the formula (IIb), the polydioxythiophenes bear positive and negative charges in the structural unit. The preparation of the polydioxythiophenes is described, for example, in EP-A 0 440 957 (=U.S. Pat. No. 5,300,575).
The polydioxythiophenes are obtained by oxidative polymerization. This gives them positive charges which are not shown in the formulae since their number and position cannot be determined definitively.
The present invention accordingly provides an electrochromic assembly comprising electrically conductive poly-(3,4-ethylenedioxythiophene) derivatives as cathodically colouring electrochromic polymers and suitable ion reservoir layers for protons. An electrolyte comprising a crosslinked or uncrosslinked polymer, a protic acid and a particular amount of a solvent is located between the electrochromic polymer layer and the ion reservoir layer. The schematic structure is shown in FIG. 1, Principle 1).
Legend for FIG. 1:
1,2: Substrate
3,4: Electrically conductive coating, one of which can act as a mirror
5: Electrochromic polymer, e.g. PEDT/PSS
6: Ion reservoir layer
7: Electrolyte containing protic acid (crosslinked or uncrosslinked)
8,9: Fine metal grid (optional)
The electrochromic polymer layer is transparent in the doped state. This can be converted into a coloured form by uptake of electrons (reduction) at the cathode with acquisition of an absorbance in the visible region of the spectrum. The oxidation which proceeds on the opposite side (anode) is linked to an exchange reaction of the ion reservoir layer with protons. However, this reaction barely contributes to generation of colour so that it does not interfere.
The present invention accordingly provides a light-stabilized electrochromic solid-phase system comprising at least one redox-active, electrically conductive polymer selected from the group consisting of poly(3,4-alkylenedioxythiophene) derivatives which can be admixed with polystyrenesulphonate to make them processible from solution or bear a solubilizing sulphonate group in a side chain. This polymer layer is preferably applied from aqueous solution, with evaporation of the solvent leaving the solid, dry polymer film on the substrate. However, it should also be able to be applied by screen printing. The substrate used is preferably an electrically conductive, transparent glass or film system, with a layer of indium-tin oxide (ITO), fluorine-doped tin oxide (FTO, K-glass), undoped tin oxide or a layer of finely divided silver serving as electrode. It is also possible for one side of the electrode to consist of a metal layer (e.g. Al, Cu, Pd) which is no longer transparent (when used in a mirror). The electrolyte comprises at least one polymer (e.g. polyethylene oxide, polyvinyl alcohol, polyvinylpiperidine), at least one protic acid (e.g. phosphoric acid) and possibly a solvent.
The present invention provides not only for use as electrochromic device in glazing of buildings or architectural glazing and as vehicle glazing or sunroof but also for use as display element, as electrochromic mirror (e.g. self-dimming automobile rear-view mirror) and use in various optical elements.
For use as a mirror, one of the two electrodes can consist of a vapour-deposited or electrochemically deposited metal coating, e.g. aluminium, silver, copper, platinum, palladium, rhodium.
The present invention further provides a light-stabilized electrochromic system in which the colour-producing electrochromic polymer compound functions simultaneously as its own electrode, as a result of which only one conductive coating of ITO , fluorine-doped tin oxide or a metal is necessary (see, FIG. 1, principle II))
Legend for FIG. 1, principle II):
1,2: Substrate
4: Electrically conductive coating which can also act as a mirror
5: Electrochromic polymer
6: Ion reservoir layer
7: Electrolyte containing protic acid (crosslinked or uncrosslinked)
8,9: Fine metal grid (optional)
A particularly advantageous aspect of the electrochromic assembly of the invention is that it can be combined with a heat protection glass (commercially available for architectural glazing purposes) explicitly as a positive structural feature for energy-saving measures in rooms into which the sun shines strongly. Further explicit electrodes of other material are therefore not necessary since the heat-protection layer limits the transmission of IR radiation and at the same time, due to its electrical conductivity, takes over the electrode function in the electrochromic assembly.
The electrochromic assembly of the invention is also notable for the fact that the electrochromic layer can also absorb IR radiation in particular regions and thus can limit the transmission of heat through the pane.
The electrochromic layer assembly of the invention is suitable as a constituent of an electrochromic device. In an electrochromic device, the light-stabilized electrochromic layer assembly of the invention serves as a medium having variable transmission, i.e. the light transmittance of the system changes under the action of an electric potential by going from a colourless state to a coloured state. The present invention therefore also provides electrochromic devices in which an electrochromic assembly according to the invention is present. Applications of this electrochromic device are in architectural glazing and in vehicles, e.g. as window pane, car sunroof, automobile rear-view mirror, display or as optical element or as constituent of information display units such as instrument displays in vehicles of any type. It can likewise be used as a window in greenhouses.
If the electrochromic device is an electrochromic display device, one or both of the two conductive layers is/are divided into electrically separate segments which are individually provided with contacts.
It is, however, also possible for only one of the two plates to have a conductive coating and be divided into segments. The segments can be separated, for example, by mechanical removal of the conductive layer, e.g. by scoring, scratching, scraping or milling or by chemical means, for example by etching using, for example, a hydrochloric acid solution of FeCl2 and SnCl2. This removal of the conductive layer can be controlled in terms of location by means of masks, e.g. masks of photoresist. However, the electrically separate segments can also be produced by targeted, e.g. by means of masks, application, e.g. sputtering or printing, of the conductive layer. The provision of the segments with contacts is carried out, for example, by means of fine strips of conductive material, so that the segment is electrically connected to a contact at the edge of the electrochromic device. These fine contact strips can consist of the same material as the conductive layer itself and, for example, be produced together with it in the division of the layer into segments, as described above. However, they can also consist, e.g. for improving the conductivity, of other material such as fine metallic conductors, for example of copper or silver. A combination of metallic material and the material of the conductive coating is also possible. These metallic conductors can, for example, be applied in fine wire form, e.g. adhesively bonded-on, or be printed on. All these techniques just described are generally known from the production of liquid crystal displays (LCDs).
In the case of displays, the displays according to the invention can be viewed in transmitted light or reflectively via mirroring.
If the electrochromic device is an electrochromic window, a fine metal grid can be vapour-deposited onto one or both electrodes. This serves to improve the surface conductivity of the substrates and is advantageous in the case of large areas in order to achieve a uniform colour.
The light-stabilized electrochromic assembly of the invention preferably incorporates at least one transparent, electrically conductive coating comprising indium-tin oxide (In2O3: SnO2 (ITO)), tin oxide (SnO2), fluorine-doped tin oxide (SnO2: F; FTO or xe2x80x9cK glassxe2x80x9d, xe2x80x9cheat protection glassxe2x80x9d), antimony-doped tin oxide, antimony-doped zinc-oxide, aluminium-doped zinc oxide or a transparent metal film having a sufficiently thin thickness, e.g. silver coating (heat protection glass) on a substrate (glass or plastic).
Other conductive polymers such as substituted or unsubstituted polythienyls, polypyrroles, polyanilines, polyactetylene or polythiophenes can also be used.
In the light-stabilized assembly of the invention, the actual electrochromic polymer can also be used advantageously as its own conductive electrode material in place of one of the abovementioned conductive coatings.
Very particular preference is given to using indium-tin oxide (In2O3: SnO2 (ITO)), zinc oxide (SnO2), fluorine-doped tin oxide (SnO2: F; FTO, xe2x80x9cK glassxe2x80x9d, xe2x80x9cheat protection glassxe2x80x9d) or a transparent silver coating having a sufficiently thin thickness (heat protection glass, e.g. (copyright)PLANITHERM from Saint-Gobain, or heat protection film).
If one of the plates is mirrored, this conductive layer can also be utilized. Particular preference is here given to using silver, aluminium, copper, platinum, palladium and rhodium.
The light-stabilized electrochromic assembly of the invention preferably includes a transparent electrolyte which can be considered a polymer electrolyte or polyelectrolyte and comprises the following components:
polymer (crosslinked or uncrosslinked)
protic acid.
Preferred polymers here are polymethyl methacrylate (PMMA), polyethylene oxide (PEO), polyvinyl alcohol (PVA), polyvinylpiperidine (PVP), polystyrenesulphonic acid (PSS), polyvinylsulphonic acid (polyVSA), poly(2-acrylamido-2-methyl-propanesulphonic acid (polyAMPS), polyethylenesulphonic acid (polyESA), polyacrylonitrile (PAN), poly(N,N,-dimethylacrylamide), poly(2-(2-methoxyethoxy)-ethoxy)phosphazene, poly(oxymethylene-oligo(oxyethylene)), polyethylene glycols (PEGs), polypropylene glycols (PPGs) or polymers based on polyepichlorohydrin or polyethers and also mixtures. Copolymers such as ethyhlene oxide-propylene oxide (EO/PO) copolymer or oxymethylene-bridged polyethylene oxides can also be used.
Particular preference is given to using polyethers and polyethylene oxides, which may also be crosslinked.
Particular preference is also given to modified siloxanes derived from, for example, gamma-glycidylpropyltrimethoxysilane. These can be, for example, variants modified by means of propylene oxide.
The electrolytes can also contain, apart from the UV absorbers, organic and/or inorganic fillers or additives. Here, the customary additives such as thermostabilizers, optical brighteners, flame retardants, flow improvers, dyes, pigments, fillers or reinforcing materials, finely divided minerals, fibrous materials, chalk, quartz flour, glass, aluminium oxide, aluminium chloride and carbon fibres can be added in customary amounts. The function of a spacer can be assumed, for example, by glass spheres, polymer particles, silica gel or sand grains having a defined size, if this is necessary.
Preferred protic acids are sulphonic acids, in particular trifluoromethanesulphonic acid, phosphoric acid or imidazole compounds. The protic acids can be present as a solution in the electrolyte or can be present in immobilized form in a polymer, for example polystyrenesulphonic acid.
Very particular preference is here given to phosphoric acid.
Substrates used in the light-stabilized electrochromic assembly of the invention are glass or various types of plastic.
Preference is given to generally transparent substrates of any type.
Particularly preferred materials are glass, specifically heat protection glass for the application as electrochromic window (in thicknesses of 10 xcexcm in the case of xe2x80x9cflexible glass, thin glassxe2x80x9d up to 3 cm) and also polyesters (e.g. polyethylene terephthalate (PET), or polyethylene naphthalate (PEN)), various types of polycarbonate (e.g. (copyright)Makrolon, APEC-HT), polysulphones, polyimides and polycycloolefins. The polymeric substrate can be used as a flexible film or as a thick plate. The substrate can also be curved, so that the assembly of layers matches the shape of the base. A flexible plastic substrate can, after construction of the total electrochromic system, also be laminated onto or adhesively bonded onto various bases such as curved glass.
The plastic substrates can be additionally provided with barrier layers against water and oxygen.
Preference is here given to TiOx, SiOx on polyester, e.g. polyethylene terephthalate, Du Pont, (cf. packaging films) or fluorinated polymers and possible combinations thereof and also barrier layers based on inorganic-organic hybrid systems.
The electrochromic assembly of the invention can, when configured as a flexible film system, be laminated or adhesively bonded as a complete electrochromic composite system onto the safety glass panes of cars. It can also be integrated into the hollow space of a composite glass pane system in architectural glazing.
The control mechanism of the electrochromic assembly is based on the reversible electrochemical doping of the electrochromic polymer which results in great colour changes, for example from colourless to blue. The assembly is controlled by means of defined voltages.
The reduction and oxidation processes in the electrochromic assembly of the invention generally occur by uptake and release of electrons at the cathode and anode respectively, with the potential difference between the electrodes preferably being from 0.1 to 5 V, very particularly preferably from 0.1 to 3 V. After switching off the electric potential, the previously achieved colour can be maintained for a prolonged period (memory effect) so that a permanent colour can be achieved with minimal energy consumption. Brief reversal of the polarity can spontaneously achieve charge neutralization and thus decoloration.
In the case of relatively large areas, the electrochromic assembly of the invention is also characterized in that it can be supplied with power by means of solar modules.
To improve wetting of the substrate, it is also possible to add a wetting agent (e.g. Fluortensid).

Arrangement based on poly-(3,4-dioxythiophene) derivatives which are electrochromically switched with protons


Pickering emulsions, which are finely disperse systems of the water-in-oil or oil-in-water type, comprising

The present invention relates to emulsifier-free finely disperse systems of the oil-in-water and water-in-oil type, preferably as cosmetic or dermatological preparations.
Emulsions are generally taken to mean heterogeneous systems which consist of two liquids which are immiscible or have only limited miscibility with one another, which are usually referred to as phases. In an emulsion, one of the two liquids is dispersed in the form of very fine droplets in the other liquid.
If the two liquids are water and oil and if oil droplets are finely dispersed in water, then this is an oil-in-water emulsion (O/W emulsion, e.g. milk). The basic character of an O/W emulsion is defined by the water. In a water-in-oil emulsion (W/O emulsion, e.g. butter), the principle is reversed, the basic character here being determined by the oil.
In order to achieve permanent dispersion of one liquid in another, emulsions in the traditional sense require the addition of an interface-active substance (emulsifier). Emulsifiers have an amphiphilic molecular structure, consisting of a polar (hydrophilic) and a nonpolar (lipophilic) molecular moiety, which are spatially separate from one another. In simple emulsions, finely disperse droplets of one phase, surrounded by an emulsifier shell, (water droplets in W/O emulsions or lipid vesicles in O/W emulsions) are present in the second phase. Emulsifiers lower the interfacial tension between the phases by positioning themselves at the interface between two liquids. At the phase boundary, they form oil/water interfacial films, which prevent irreversible coalescence of the droplets. Emulsions are frequently stabilized using emulsifier mixtures.
Traditional emulsifiers can, depending on their hydrophilic molecular moiety, be divided into ionic (anionic, cationic and amphoteric) and nonionic:
The most well-known example of an anionic emulsifier is soap, which is usually the term used for the water-soluble sodium or potassium salts of saturated or unsaturated higher fatty acids.
Important examples of cationic emulsifiers are quaternary ammonium compounds.
The hydrophilic molecular moiety of nonionic emulsifiers frequently consists of glycerol, polyglycerol, sorbitans, carbohydrates and polyoxyethylene glycols, and, in most cases, is linked to the lipophilic molecular moiety via ester and ether bonds. The lipophilic molecular moiety usually consists of fatty alcohols, fatty acids or isofatty acids.
By varying the structure and the size of the polar and nonpolar molecular moiety, the lipophilicity and hydrophilicity of emulsifiers can be varied within wide limits.
A decisive factor for the stability of an emulsion is the correct choice of emulsifiers. The characteristics of all substances present in the system are to be taken into consideration here. In the case of, for example, skincare emulsions, polar oil components and, for example, UV filters lead to instability. As well as the emulsifiers, therefore, other stabilizers are also used which, for example, increase the viscosity of the emulsion and/or act as protective colloid.
Emulsions are an important type of product in the field of cosmetic and/or dermatological preparations.
Cosmetic preparations are essentially used for skin care. The main aim of skin care in the cosmetics sense is to strengthen or rebuild the skin""s natural function as a barrier against environmental influences (e.g. dirt, chemicals, microorganisms) and against the loss of endogenous substances (e.g. water, natural fats, electrolytes). If this function becomes impaired, increased resorption of toxic or allergenic substances or attack by microorganisms may result, leading to toxic or allergic skin reactions.
Another aim of skin care is to compensate for the loss by the skin of lipids and water caused by daily washing. This is particularly important if the natural regeneration ability is inadequate. Furthermore, skincare products should protect against environmental influences, in particular against sun and wind, and delay skin ageing.
Cosmetic preparations are also used as deodorants. Such formulations are used to control body odour, which is produced when fresh perspiration, which is in itself odourless, is decomposed by microorganisms.
Medicinal topical compositions usually comprise one or more medicaments in an effective concentration. For the sake of simplicity, in order to distinguish clearly between cosmetic and medicinal use and corresponding products, reference is made to the legal provisions in the Federal Republic of Germany (e.g. Cosmetics Directive, Foods and Drugs Act).
The use of customary emulsifiers in cosmetic or dermatological preparations is in itself acceptable. Nevertheless, emulsifiers, like ultimately any chemical substance, may in certain circumstances cause allergic reactions or reactions based on oversensitivity of the user.
For example, it is known that certain light dermatoses are triggered by certain emulsifiers, but also by various fats and simultaneous exposure to sunlight. Such light dermatoses are also called xe2x80x9cMallorca acnexe2x80x9d. There has thus been no lack of attempts to reduce the amount of customary emulsifiers to a minimum, in the ideal case even to zero.
A reduction in the required amount of emulsifier can, for example, be achieved by taking advantage of the fact that very finely divided solid particles have an additional stabilizing action. The solid substance accumulates at the oil/water phase boundary in the form of a layer, as a result of which coalescence of the disperse phases is prevented. It is not the chemical properties of the solid particles which are of fundamental importance here, but the surface properties.
Around 1910, Pickering prepared paraffin/water emulsions which were stabilized merely by the addition of various solids, such as basic copper sulphate, basic iron sulphate or other metal sulphates. This type of emulsion is thus also referred to as a Pickering emulsion.
The original forms of Pickering emulsions initially surfaced, as it were, as undesired secondary effects in a variety of industrial processes, such as, for example, in secondary oil recovery, the extraction of bitumen from tar sand and other separation processes involving two immiscible liquids and fine, dispersed solid particles. These are generally W/O emulsions which are stabilized by mineral solids. Accordingly, investigation of corresponding systems, such as, for example, the oil/water/soot or oil/water/slate dust systems was initially the focus of research activity.
Basic experiments have shown that one characteristic of a Pickering emulsion is that the solid particles are arranged at the interface between the two liquid phases, where they form, as it were, a mechanical barrier against the combining of the liquid droplets.
It is a relatively new technical development to use Pickering emulsions as a base for cosmetic or dermatological preparations.
One way of achieving solids stabilization in the sense of a pickering emulsion in a cosmetic or dermatological preparation is, according to May-Alert (Pharmazie in unserer Zeit [Pharmacy in our time], Vol. 15, 1986, No. 1, 1-7) for example, to use emulsifier mixtures which comprise both anionic and cationic surfactants. Since mixing anionic and cationic surfactants always results in the precipitation of insoluble, electroneutral compounds, deliberate precipitation of these neutral surfactants in the oil/water interface makes it possible to achieve additional solids stabilization.
European Laid-open Specification 0 686 391, moreover, describes emulsions of the water-in-oil type which are free from surface-active substances and are stabilized only by solids. Stabilization is achieved here using spherical polyalkylsilsesquioxane particles which have a diameter of from 100 nm up to 20 xcexcm. These emulsions can be referred to as Pickering emulsions according to that mentioned above.
Pickering emulsions are stabilized by the use of suitable solids or pigments. However, the preparations of the prior art generally have the disadvantage that they are limited to a narrow field of application or a restricted choice of starting materials since they can only be stably formulated in this manner. For many areas of cosmetics (e.g. for the field of face care), Pickering emulsions of the prior art have unsatisfactory cosmetic properties.
In addition, when relevant preparations are applied to the skin, solids can leave behind a dry and sometimes dull impression. Even preparations with a pigment content of 1% by weight produce a dull feel on the skin following their application, which increases further with higher pigment concentrations. In some cases, therefore, pigment-containing preparations may not even be marketable since they are not accepted or are viewed negatively by the consumer.
The object was therefore to remedy the disadvantages of the prior art. In particular, the intention was to provide preparations which do not leave behind a dry or dull impression on the skin.
Furthermore, it was an object of the invention to develop cosmetic and dermatological bases for cosmetic and dermatological preparations which are characterized by good skin tolerability.
In addition, an object of the present invention was to provide products with the widest possible variety of applications. For example, the intention was to provide bases for preparation forms such as cleansing emulsions, facecare and bodycare preparations or deodorants, but also distinctly medicinal-pharmaceutical presentations, for example preparations against acne and other skin conditions.
It was surprising and in no way predictable by the person skilled in the art that Pickering emulsions, which are finely disperse systems of the water-in-oil or oil-in-water type, comprising
(1) an oil phase,
(2) a water phase,
(3) at least one type of microfine particles which
a) have an average particle size of less than 200 nm, which
b) display both hydrophilic and lipophilic properties, i.e. which have amphiphilic character, and are dispersible both in water and in oil and which
c) have optionally been coated on the surface,
(4) at least one polymeric moisturizer and
(5) at most 0.5% by weight of one or more emulsifiers,
overcome the disadvantages of the prior art.
According to the invention, it is particularly advantageous if the preparations comprise significantly less than 0.5% by weight of one or more emulsifiers or are even entirely free from emulsifiers.
The preparations according to the invention are extremely satisfactory preparations in every respect which surprisingly have excellent cosmetic properties, do not leave a dry or dull impression on the skin and are characterized by excellent skin tolerability. In addition, compared with traditional Pickering emulsions, the preparations according to the invention have considerably higher stability and are therefore suitable in particular to serve as bases for preparation forms having diverse application purposes.
In addition, it was surprising that preparations according to the invention which are in the form of a sunscreen exhibit higher effectiveness than customary sunscreen formulations.
Although the prior art recognizes, in addition to Pickering emulsions, emulsifier-free, finely disperse cosmetic or dermatological preparations, which are generally referred to as hydrodispersions and which are dispersions of a liquid, semisolid or solid inner (discontinuous) lipid phase in an outer aqueous (continuous) phase, the prior art was unable to point the way to the present invention.
In the case of hydrodispersions of a liquid lipid phase in an outer aqueous phase, the stability can, for example, be ensured by constructing in the aqueous phase a gel structure in which the lipid droplets are stably suspended.
German Laid-open Specification 44 25 268 describes stable finely disperse, emulsifier-free cosmetic or dermatological preparations of the oil-in-water type which, in addition to an oil and a water phase, comprise one or more thickeners from the group of acrylic acid polymers, polysaccharides and the alkyl ethers thereof, where for these thickeners a lowering of the surface tension must not be measurable.
German Laid-open Specification 43 03 938 discloses cosmetic or dermatological light protection formulations based on similar hydrodispersions which are essentially free from emulsifiers, where inorganic micropigments are incorporated into the lipid phase of the hydrodispersion and serve as UV filter substances.
By contrast, for the purposes of the present invention, O/W Pickering emulsions are obtainable by firstly dispersing in the water phase amphiphilic particles according to the invention which are suitable for the preparation of O/W Pickering emulsions, and then combining the water phase with the fatty phase. By contrast, W/O Pickering emulsions according to the invention are obtainable by dispersing amphiphilic particles according to the invention and suitable for the preparation of W/O Pickering emulsions in the fatty phase.
Polymeric moisturizers in cosmetic and pharmaceutical preparations are known per se. Moisturizers are defined as substances or mixtures of substances which impart to cosmetic or dermatological preparations the property of reducing the release of moisture from the horny layer (also called transepidermal water loss (TEWL) ) when applied to or distributed on the surface of the skin.
It is particularly advantageous to use polymeric moisturizers from the group of polysaccharides which are water-soluble and/or water-swellable and/or gellable using water. Particularly advantageous are, for example, hyaluronic acid, chitosan and/or a fucose-rich polysaccharide which is listed in the Chemical Abstracts under the registry number 178463-23-5 and is available, for example, under the name Fucogel(copyright) 1000 from SOLABIA S.A. The latter is characterized by the following structural elements:
Hyaluronic acid is characterized by the structure
It is particularly preferable to use hyaluronic acids having molecular weights between 30,000 and 8,000,000, in particular those having molecular weights between 500,000 and 1,500,000.
Chitosan is characterized by the following structural formula:
in which n assumes values up to about 10,000, X is either the acetyl radical or hydrogen. Chitosan is formed by deacetylation and partial depolymerization (hydrolysis) of chitin, which is characterized by the structural formula
Chitin is an essential constituent of the ectoskeleton of arthropods (e.g. insects, crabs, spiders) and is also found in the supporting tissue of other organisms (e.g. molluscs, algae, fungi).
Chitosan is a raw material known in hair care. It is suitable, to a higher degree that the chitin on which it is based, as a thickener or stabilizer and improves the adhesion and water resistance of polymeric films. A representative of a large number of literature references for the prior art is: H. P. Fiedler, xe2x80x9cLexikon der Hilfsstoffe fxc3xcr Pharmazie, Kosmetik und angrenzende Gebietexe2x80x9d [Lexicon of auxiliaries for pharmacy, cosmetics and related fields], 3rd edition 1989, Editio Cantor, Aulendorf, p. 293, keyword xe2x80x9cChitosanxe2x80x9d.
According to the invention, preference is given to chitosans having a degree of deacetylation of greater than 25%, in particular greater than from 55 to 99% [determined by means of 1H-NMR].
It is advantageous to chose chitosans having molecular weights between 3000 and 2,000,000 and in particular those having molecular weights between 100,000 and 1,000,000 [determined by means of gel permeation chromatography].
The chitosan is usually incorporated by adjusting a suspension of chitosan, in particular of micronized chitosan, in water to a pH of 3.5-5.5 using organic or inorganic acids, a solution of the chitosan being obtained, normally by stirring. A clear solution of 2% by weight of chitosan in 1.2% of lactic acid (90% strength aqueous solution) obtainable in this way have, for example, a viscosity according to Viscotester VT02 (Haake) which is in the range from 100 to 10,000 mPaxc2x7s, preferably from 200 to 5000 mPaxc2x7s.
The total amount of one or more polymeric moisturizers in the finished cosmetic or dermatological preparations is advantageously chosen to be less than 10.0% by weight, preferably between 0.5 and 5.0% by weight, based on the total weight of the preparation.
It is also advantageous, but not obligatory, for the Pickering emulsions according to the invention to comprise other auxiliaries which can contribute to reducing or preventing a dull or dry feel on the skin following their application, where it is possible that the main purpose of these substances is a different one. Preferably, these substances are, for example, chosen from the group of unsymmetrically substituted s-triazine derivatives, cyclodextrins and film formers, it being possible for these substances to be present either individually or in a mixture.
The cosmetic properties of the Pickering emulsions according to the invention can additionally, for example, be further improved by using oils in the oil phase which have a viscosity of less than 30 mPaxc2x7s, in particular of less than 20 mPaxc2x7s (determined using a rheometer from Contraves (Rheomat 108E) at a shear gradient of 500/s and a temperature of 25xc2x0 C.).
Microfine Particles:
The amphiphilic character of the microfine particles according to the invention is evident, for example, from the fact that they are dispersible both in water and in oil.
It is advantageous to choose the average particle diameter of the particles used to be between 1 nm and 200 nm, particularly advantageously between 5 nm and 100 nm.
It is also advantageous to choose the concentration of all amphiphilic particles according to the invention to be greater than 0.1% by weight, particularly advantageously between 0.1% by weight and 30% by weight, based on the total weight of the preparations.
For the purposes of the present invention, advantageous particles are all those which are suitable for stabilizing Pickering W/O or Pickering O/W emulsions. It is essentially insignificant for the present invention in which of the potentially naturally occurring modifications the particles are present.
To stabilize the Pickering emulsions, preference is given to using untreated, virtually pure pigment particles, in particular those which can be used as dyes in the food industry and/or as absorbers of UV radiation in sunscreens. Examples of advantageous pigments are the zinc oxide pigments available from Merck which are available under the trade names Zinkoxid neutral from Haarmann and Reimer or NanoX from Harcros Chemical Group.
For the purposes of the present invention, Pickering emulsions are likewise advantageously stabilized by inorganic pigments which have been surface-treated (xe2x80x9ccoatedxe2x80x9d) to repel water, where at the same time the intention is to form or retain the amphiphilic character. This surface-treatment can consist in providing the pigments with a thin hydrophobic layer by processes known per se.
One such process, which is described below using titanium dioxide as an example, consists in, for example, producing the hydrophobic surface layer according to the following reaction
nTiO2+m(RO)3Sixe2x80x94Rxe2x80x2xe2x86x92nTiO2 (surf.).
n and m are arbitrary stoichiometric parameters, and R and Rxe2x80x2 are the desired organic radicals. Particularly advantageous are TiO2 pigments, for example those coated with aluminium stearate, available under the trade name MT 100 T from TAYCA.
A further advantageous coating of the inorganic pigments consists of dimethylpolysiloxane (also: dimethicone), a mixture of completely methylated, linear siloxane polymers which are terminally blocked with trimethylsiloxy units. For the purposes of the present invention, particularly advantageous pigments are zinc oxide pigments which are coated in this way.
Also advantageous is a coating of the inorganic pigments with a mixture of dimethylpolysiloxane, in particular dimethylpolysiloxane having an average chain length of from 200 to 350 dimethylsiloxane units, and silica gel, which is also referred to as simethicone. It is particularly advantageous if the inorganic pigments have been additionally coated with aluminium hydroxide or hydrated aluminium oxide (also: alumina, CAS No.: 1333-84-2). Particularly advantageous are titanium dioxides which have been coated with simethicone and alumina, it being possible for the coating to also comprise water. One example thereof is the titanium dioxide available under the trade name Eusolex T2000 from Merck.
For the purposes of the present invention it is also advantageous to use a mixture of different pigment types either within a crystal, for example as mixed iron oxide, or by combination of two or more pigment types within a preparation.
The Pickering emulsions are also preferably stabilized by boron nitrides, for example by the boron nitrides listed below:
It is advantageous to choose the average particle diameter of the boron nitride particles used to be less than 20 xcexcm, particularly advantageously less than 15 xcexcm.
For the purposes of the present invention, Pickering emulsions are likewise advantageously stabilized by boron nitride particles which have been surface-treated (xe2x80x9ccoatedxe2x80x9d) to repel water, where at the same time the intention is to form or retain the amphiphilic character.
An advantageous coating of the boron nitride particles consists of dimethylpolysiloxane (dimethicone). The boron nitride particles treated with dimethicone and available from Carborundum under the trade name Trxc3xa8s BN(copyright) UHP 1106 are advantageous, for example.
Also advantageous is a coating of the boron nitride particles with polymethylhydrogensiloxane, a linear polysiloxane which is also referred to as methicone. Advantageous boron nitride particles treated with methicone are, for example, those available from Carborundum under the trade name Trxc3xa8s BN(copyright) UHP 1107.
It is also advantageous to stabilize the Pickering emulsions according to the invention using microfine polymer particles.
For the purposes of the present invention, examples of advantageous microfine polymer particles are polycarbonates, polyethers, polyethylenes, polypropylenes, polyvinyl chloride, polystyrene, polyamides, polyacrylates and the like.
Advantageous according to the invention are, for example, microfine polyamide particles which are available under the trade name SP-500 from TORAY. Also advantageous are polyamide 6 (also: nylon 6) and polyamide 12 (also: nylon 12) particles. Polyamide 6 is the polyamide formed from xcex5-aminocaproic acid (6-aminohexanoic acid) or xcex5-caprolactam [poly(xcex5-caprolactam)], and polyamide 12 is a poly(xcex5-laurolactam) from xcex5-laurolactam. For the purposes of the present invention, Orgasol(copyright) 1002 (polyamide 6) and Orgasol(copyright) 2002 (polyamide 12) from ELF ATOCHEM, for example, are advantageous.
Other advantageous polymer particles are microfine polymethacrylates. Such particles are available, for example, under the trade name POLYTRAP(copyright) from DOW CHEMICAL.
It is particularly advantageous, but not obligatory, if the microfine polymer particles used have been surface-coated. This surface-treatment can consist in providing the pigments with a thin hydrophilic layer by processes known per se. Advantageous coatings consist, for example, of TiO2, ZrO2 or also other polymers, such as, for example, polymethyl methacrylate.
Particularly advantageous microfine polymer particles for the purposes of the present invention are also obtainable by the process, described in U.S. Pat. No. 4,898,913, for the hydrophilic coating of hydrophobic polymer particles.
It is advantageous to choose the average particle diameter of the microfine polymer particles used to be less than 100 xcexcm, particularly advantageously less than 50 xcexcm. In this connection, it is essentially insignificant in which form (platelets, rods, spherules, etc.) the polymer particles used are present.
In addition, it is advantageous to stabilize the Pickering emulsions according to the invention using modified polysaccharides.
For the purposes of the present invention, modified polysaccharides are, for example, obtainable by reaction of starch with mono-, bi- or polyfunctional reagents or oxidizing agents in reactions which proceed in a largely polymer-analogous manner.
Such reactions are based essentially on modifications of the hydroxyl groups of the polyglucans by etherification, esterification or selective oxidation. This produces, for example, so-called starch ethers and starch esters of the general structural formula
in which R can, for example, be a hydrogen and/or an alkyl and/or an aralkyl radical (in the case of starch ethers) or a hydrogen and/or an organic and/or inorganic acid radical (in the case of starch esters). Starch ethers and starch esters are advantageous, modified polysaccharides for the purposes of the present invention.
Particularly advantageous starch ethers are, for example, those which are obtainable by etherification of starch with tetramethylolacetylenediurea and which are referred to as non-mucilaginous starch (nonswelling starch).
Also particularly advantageous are starch esters and salts thereof, for example the sodium and/or aluminium salts of half-esters of starch which have low degrees of substitution, in particular sodium starch n-octenyl succinate of the structural formula (II) in which R is characterized by the following structure
and which is available, for example, under the trade name Amiogum(copyright) 23 from CERESTAR, and aluminium starch octenyl succinates, in particular those available under the trade names Dry Flo(copyright) Elite LL and Dry Flo(copyright) PC from CERESTAR.
It is advantageous to choose the average particle diameter of the modified polysaccharide used to be less than 20 xcexcm, particularly advantageously less than 15 xcexcm.
The list of given modified polysaccharides which are able to stabilize Pickering emulsions according to the invention is of course not intended to be limiting. For the purposes of the present invention, modified polysaccharides are obtainable in a large number of ways known per se, both of a chemical and a physical nature.
The amphiphilic particles mentioned above are highly suitable both for stabilizing W/O Pickering emulsions and also for stabilizing O/W Pickering emulsions. Microfine particles according to the invention are given below which advantageously stabilize one of the two emulsion types W/O or O/W in particular.
W/O Pickering Emulsions:
The water phase content of the W/O Pickering emulsions according to the invention is preferably chosen from the range from 0.5 to 75% by weight, based on the total weight of the formulations.
Also advantageous for the stabilization of W/O Pickering emulsions are, in particular, magnesium silicates (also: talc), for example those obtainable under the trade name Talkum Micron from Grolmann.
O/W Pickering Emulsions:
The fatty phase content of the O/W Pickering emulsions according to the invention is preferably chosen from the range from 0.5 to 75% by weight, based on the total weight of the formulations.
For the purposes of the present invention, untreated, virtually pure pigment particles are also particularly advantageous for stabilizing O/W Pickering emulsions, for example titanium dioxide pigments, in particular those which are obtainable under the trade name KRONOS(copyright) 1171 (TiO2) from Kronos Titan.
For the purposes of the present invention, O/W Pickering emulsions are also particularly advantageously stabilized by metal oxide particles which have been coated with aluminium hydroxide and/or silicon dioxide. Advantageous variants are, for example, titanium dioxide particles which are obtainable under the name EUSOLEX(copyright) TA from Merck.
In addition, it is advantageous, but not obligatory, to combine the microfine particles according to the invention with other amphiphilic particles, which in some circumstances can also contribute to the stabilization of the Pickering emulsions.
Such particles are, for example, titanium dioxide pigments which have been coated with octylsilanol, and/or silicon dioxide particles which have been surface-treated to repel water. Suitable silicon dioxide particles are, for example, spherical polyalkylsilsesquioxane particles, as mentioned in European Laid-open Specification 0 686 391. Such polyalkylsilsesquioxane particles are, for example, obtainable under the trade names Aerosil R972 and Aerosil 200V from Degussa. Suitable titanium dioxide particles are obtainable under the trade name T805, likewise from Degussa.
The Pickering emulsions according to the invention can be used as bases for cosmetic or dermatological formulations. These can have the customary composition and be used, for example, for the treatment and care of the skin, as lipcare products, as deodorant products and as make-up products or make-up remover products in decorative cosmetics or as light protection preparations. For use, the cosmetic and dermatological preparations according to the invention are applied to the skin in sufficient amounts in the manner customary for cosmetics.
Accordingly, for the purposes of the present invention, cosmetic or topical dermatological compositions may, depending on their structure, be used, for example, as skin-protection creams, cleansing milks, sunscreen lotions, nourishing creams, day creams or night creams, etc. In some instances, it is possible and advantageous to use the compositions according to the invention as bases for pharmaceutical formulations.
The cosmetic and dermatological preparations according to the invention can comprise cosmetic auxiliaries, as are customarily used in such preparations, e.g. preservatives, bactericides, perfumes, antifoams, dyes, pigments which have a colouring effect, further thickeners, emollients, moisturizers and/or humectants, fats, oils, waxes and other customary constituents of a cosmetic or dermatological formulation, such as alcohols, polyols, polymers, foam stabilizers, electrolytes, organic solvents or silicone derivatives.
Pickering emulsions according to the invention may also comprise thickeners to improve the tactile properties of the emulsion.
In particular, the Pickering emulsions according to the invention may also comprise antioxidants. According to the invention, favourable antioxidants which can be used are any antioxidants suitable or conventional for cosmetic and/or dermatological applications.
The antioxidants are advantageously chosen from the group consisting of amino acids (e.g. glycine, histidine, tyrosine, tryptophan) and derivatives thereof, imidazoles, (e.g. urocanic acid) and derivatives thereof, peptides, such as D,L-carnosine, D-carnosine, L-carnosine and derivatives thereof (e.g. anserine), carotenoids, carotenes (e.g. xcex1-carotene, xcex2-carotene, lycopene) and derivatives thereof, chlorogenic acid and derivatives thereof, lipoic acid and derivatives thereof (e.g. dihydrolipoic acid), aurothioglucose, propylthiouracil and other thiols (e.g. thioredoxin, glutathione, cysteine, cystine, cystamine and the glycosyl, N-acetyl, methyl, ethyl, propyl, amyl, butyl and lauryl, palmitoyl, oleyl, xcex3-linoleyl, cholesteryl and glyceryl esters thereof) and the salts thereof, dilauryl thiodipropionate, distearyl thiodipropionate, thiodipropionic acid and derivatives thereof (esters, ethers, peptides, lipids, nucleotides, nucleosides and salts) and sulphoximine compounds (e.g. buthionine sulphoximines, homocysteine sulphoximine, buthionine sulphones, penta-, hexa-, hepta-thionine sulphoximine) in very low tolerated doses (e.g. pmol to xcexcmol/kg), and also (metal) chelating agents (e.g. xcex1-hydroxy fatty acids, palmitic acid, phytic acid, lactoferrin), xcex1-hydroxy acids (e.g. citric acid, lactic acid, malic acid), humic acid, bile acid, bile extracts, bilirubin, biliverdin, EDTA, EGTA and derivatives thereof, unsaturated fatty acids and derivatives thereof (e.g. xcex3-linolenic acid, linoleic acid, oleic acid), folic acid and derivatives thereof, ubiquinone and ubiquinol and derivatives thereof, vitamin C and derivatives (e.g. ascorbyl palmitate, Mg ascorbyl phosphate, ascorbyl acetate), tocopherols and derivatives (e.g. vitamin E acetate), vitamin A and derivatives (vitamin A palmitate) and coniferyl benzoate of benzoin resin, rutinic acid and derivatives thereof, xcex1-glycosylrutin, ferulic acid, furfurylideneglucitol, camosine, butylated hydroxytoluene, butylated hydroxyanisole, nordihydroguaiac acid, nordihydroguaiaretic acid, trihydroxybutyrophenone, uric acid and derivatives thereof, mannose and derivatives thereof, zinc and derivatives thereof (e.g. ZnO, ZnSO4), selenium and its derivatives (e.g. selenomethionine), stilbenes and their derivatives (e.g. stilbene oxide, trans-stilbene oxide), and the derivatives (salts, esters, ethers, sugars, nucleotides, nucleosides, peptides and lipids) of said active substances which are suitable according to the invention.
The amount of the abovementioned antioxidants (one or more compounds) in the preparations according to the invention is preferably from 0.001 to 30% by weight, particularly preferably from 0.05-20% by weight, in particular 1-10% by weight, based on the total weight of the preparation.
If vitamin E and/or derivatives thereof are used as the antioxidant or antioxidants, their respective concentrations are advantageously chosen from the range of 0.001-10% by weight, based on the total weight of the formulation.
If vitamin A or vitamin A derivatives or carotenes or derivatives thereof are used as the antioxidant or antioxidants, their respective concentrations are advantageously chosen from the range of 0.001-10% by weight, based on the total weight of the formulation.
Cosmetic and dermatological preparations which are in the form of a sunscreen are also favourable. These preferably comprise at least one UV-A filter substance and/or at least one UV-B filter substance and/or at least one further inorganic pigment selected from the group consisting of the oxides of iron, zirconium, silicon, manganese, aluminium, cerium and mixtures thereof and also modifications in which the oxides are the active agents.
For the purposes of the present invention, it is, however, also advantageous to provide such cosmetic and dermatological preparations whose main purpose is not protection against sunlight, but which nevertheless comprise substances which protect against UV. For example, UV-A and UV-B filter substances are commonly incorporated into day creams.
Preparations according to the invention can advantageously comprise substances which absorb UV radiation in the UV-B region, the total amount of filter substances being, for example, from 0.1% by weight to 30% by weight, preferably from 0.5 to 10% by weight, in particular from 1.0 to 6.0% by weight, based on the total weight of the preparations, in order to provide cosmetic preparations which protect the hair and/or the skin from the whole of ultraviolet radiation.
If the emulsions according to the invention comprise UV-B filter substances, the latter may be oil-soluble or water-soluble. Examples of oil-soluble UV-B filters which are advantageous according to the invention are:
3-benzylidenecamphor derivatives, preferably 3-(4-methylbenzylidene)camphor, 3-benzylidenecamphor;
4-aminobenzoic acid derivatives, preferably 2-ethylhexyl 4-(dimethylamino)benzoate, amyl 4-(dimethylamino)benzoate;
esters of cinnamic acid, preferably 2-ethylhexyl 4-methoxycinnamate, isopentyl 4-methoxycinnamate;
esters of salicylic acid, preferably 2-ethylhexyl salicylate, 4-isopropylbenzyl salicylate, homomenthyl salicylate,
derivatives of benzophenone, preferably 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-4xe2x80x2-methylbenzophenone, 2,2xe2x80x2-dihydroxy-4-methoxybenzophenone;
esters of benzalmalonic acid, preferably di(2-ethylhexyl) 4-methoxybenzalmalonate,
triazine derivatives which are symmetrical with regard to the C3 axis of the triazine parent substance, preferably tris(2-ethylhexyl) 4,4xe2x80x2,4xe2x80x3-(1,3,5-triazin-2,4,6-triyltriimino)trisbenzoate,
benzotriazole derivatives, preferably 2,2xe2x80x2-methylenebis(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3, -tetramethylbutyl)phenol)
and UV filters bonded to polymers.
Examples of advantageous water-soluble UV-B filter substances are:
salts of 2-phenylbenzimidazole-5-sulphonic acid, such as its sodium, potassium or triethanolammonium salts, and the sulphonic acid itself;
sulphonic acid derivatives of benzophenones, preferably 2-hydroxy-4-methoxybenzophenone-5-sulphonic acid and salts thereof;
sulphonic acid derivates of 3-benzylidenecamphor, such as, for example, 4-(2-oxo-3-bornylidenemethyl)benzenesulphonic acid, 2-methyl-5-(2-oxo-3-bornylidene-methyl)sulphonic acid and salts thereof.
The list of UV-B filters mentioned which can be used in the Pickering emulsions according to the invention is, of course, not intended to be limiting.
It can also be advantageous to use UV-A filters in Pickering emulsions according to the invention which have hitherto customarily been present in cosmetic preparations. These substances are preferably derivatives of dibenzoylmethane, in particular 1-(4xe2x80x2-tert-butylphenyl)-3-(4xe2x80x2-methoxyphenyl)propane-1,3-dione and 1-phenyl-3-(4xe2x80x2-isopropylphenyl)-propane-1,3-dione.
Other advantageous UV-A filter substances are phenylene-1,4-bis(2-benzimidazyl)-3,3xe2x80x2-5,5xe2x80x2-tetrasulphonic acid:
and its salts, particularly the corresponding sodium, potassium or triethanolammonium salts, in particular the bis-sodium salt of phenylene-1,4-bis(2-benzimidazyl)-3,3xe2x80x2-5,5xe2x80x2-tetrasulphonic acid:
and 1,4-di(2-oxo-10-sulfo-3-bornylidenemethyl)benzene and salts thereof (particularly the corresponding 10-sulfato compounds, in particular the corresponding sodium, potassium or triethanolammonium salt), which is also referred to as benzene-1,4-di(2-oxo-3-bornylidenemethyl-10-sulphonic acid) and is characterized by the following structure:
Preparations which comprise UV-A filters are also provided by the invention. The amounts which can be used are those used for the UV-B combination.
Preparations according to the invention can also be advantageously used as bases for cosmetic deodorants and antiperspirants, so that a particular embodiment of the present invention relates to Pickering emulsions as bases for cosmetic deodorants.
Cosmetic deodorants are used to control body odour which arises when fresh perspiration, which is in itself odourless, is decomposed by microorganisms. Customary cosmetic deodorants are based on various modes of action.
In antiperspirants, astringents, mainly aluminium salts, such as aluminium hydroxychloride (aluminium chlorohydrate), reduce the formation of perspiration.
The use of antimicrobial substances in cosmetic deodorants can reduce the bacterial flora of the skin. In an ideal situation, only the microorganisms which cause the odour should be effectively reduced. The flow of perspiration itself is not influenced as a result, and in ideal circumstances, only microbial decomposition of perspiration is stopped temporarily.
The combination of astringents and antimicrobial active substances in one and the same composition is also common.
All active ingredients common for deodorants or antiperspirants can advantageously be used, for example odour concealers, such as customary perfume constituents, odour absorbers, for example the phyllosilicates described in Laid-open Patent Specification DE 40 09 347, of these in particular montmorillonite, kaolinite, illite, beidellite, nontronite, saponite, hectorite, bentonite, smectite, and also, for example, zinc salts of ricinoleic acid. Antibacterial agents are also suitable to be incorporated into the novel W/O emulsion sticks. Advantageous substances are, for example, 2,4,4xe2x80x2-trichloro-2xe2x80x2-hydroxy diphenyl ether (Irgasan), 1,6-di(4-chlorophenylbiguanido)hexane (chlorhexidine), 3,4,4xe2x80x2-trichlorocarbanilide, quaternary ammonium compounds, oil of cloves, mint oil, thyme oil, triethyl citrate, farnesol (3,7,11-trimethyl-2,6,10-dodecatrien-1-ol) and also the active ingredients or active ingredient combinations described in the Laid-open Patent Specifications DE-A-37 40 186, DE-A-39 38 140, DE-A-42 04 321, DE-A-42 29 707, DE-A-43 09 372, DE-A-44 11 664, DE-A-1 95 41 967, DE-A-1 95 43 695, DE-A-1 95 43 696, DE-A-1 95 47 160, DE-A-1 96 02 108, DE-A-1 96 02 110, DE-A-196 02 111, DE-A-196 31 003, DE-A-196 31 004 and DE-A-196 34 019, and the Patent Specifications DE-42 29 737, DE-42 37 081, DE-43 24 219, DE-44 29 467, DE-44 23410 and DE-195 16705. Sodium hydrogencarbonate can also be used advantageously.
The list of specified active ingredients and active ingredient combinations is of course not intended to be limiting.
The amount of antiperspirant active ingredients or deodorants (one or more compounds) in the preparations is preferably from 0.01 to 30% by weight, particularly preferably from 0.1 to 20% by weight, in particular 1-10% by weight, based on the total weight of the preparation.

Emulsifier-free finely disperse systems of the oil-in-water and water-in-oil type

Abstract: (1) an oil phase,

Abstract: (2) a water phase,

Abstract: b) display both hydrophilic and lipophilic properties, and are dispersible both in water and in oil and which

Abstract: (5) at most 0.5% by weight of one or more emulsifiers.


The disclosed systems and methods emphasize driving LEDs in series and in parallel with the same LED driver chip and a single inductor. For creating overlap, the systems and methods of LED color overlap disclosed herein take advantage of the fact that green and blue LEDs have the same voltage. Thus, green and blue LEDs can be driven in parallel as needed. LED suppliers can screen parts for sufficiently close voltage matching between green and blue LEDs. This is especially true when using green LED die based on a blue die with a green phosphor. Cyan may be produced by driving a green LED and a blue LED in parallel. White may produced by driving a green LED and a blue LED in parallel and a red LED in series with this green and blue parallel pair.

A light-emitting diode is a semiconductor light source. LEDs are used as indicator lamps in many devices and are increasingly used for other lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light; but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.
When a light-emitting diode is forward biased (switched on), electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence and the color of the light (corresponding to the energy of the photon) is determined by the energy gap of the semiconductor. An LED is often small in area (less than 1 mm2), and integrated optical components may be used to shape its radiation pattern. LEDs present many advantages over incandescent light sources including lower energy consumption, longer lifetime, improved robustness, smaller size, faster switching, and greater durability and reliability. LEDs powerful enough for room lighting are relatively expensive and require more precise current and heat management than compact fluorescent lamp sources of comparable output.
Light-emitting diodes are used in applications as diverse as replacements for aviation lighting, automotive lighting (particularly brake lamps, turn signals and indicators) as well as in traffic signals. The compact size, the possibility of narrow bandwidth, switching speed, and extreme reliability of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are also useful in advanced communications technology. Infrared LEDs are also used in the remote control units of many commercial products including televisions, DVD players, and other domestic appliances. Recent strides have been accomplished in introducing LEDs into projectors, including digital light processing projectors. LED Drivers in projectors that support color overlap for yellow, cyan, magenta, and white, using red, green, and blue LEDs, normally require three LED driver chips so that two LEDs can be driven at the same time. For example, to achieve yellow, the red LED driver and green LED driver are enabled at the same time. The three LED driver chips, and the three inductors to go with them, are expensive and large in size. This is an issue, especially in small pico-projectors such as those embedded in cell phones. Therefore, there are heretofore unaddressed needs with previous solutions.

Systems and methods of LED color overlap